1. Field of the Invention
The present invention relates generally to a graphical user interface and, more particularly, to graphically annotating a measurement display of a signal measurement system.
2. Related Art
Conventional signal measurement systems such as digital oscilloscopes sample, record and display time-varying analog signals. Samples of an input signal are taken and quantized, and the resultant digital representations are stored in a waveform memory under the control of a sampling clock. The acquired data may be subsequently read out as locations in memory are sequentially addressed by a clock signal to provide digital data that can be converted to a time-varying output signal for a waveform display. The sampling clock may be operated at one of several selectable rates depending upon the frequency content of the input signal. The selection of the portion of the analog input signal sampled and stored is determined by appropriate triggering circuitry to enable the operator to display the desired portion of the waveform.
There are many types of display elements that can be presented in signal measurement systems in general and test and measurement instruments in particular. For example, in addition to the waveforms representing the signals currently received at the channel inputs, waveforms referred to as function waveforms may also be displayed. Function waveforms are waveforms created by processing one or more signal waveforms. Such processing may include, for example, performing arithmetic manipulations on a signal waveform or combining multiple input signal waveforms in some predetermined manner. The resulting function waveforms are stored in a display memory for subsequent retrieval and display. In addition, memory waveforms may also be displayed. Memory waveforms are waveforms which have been previously captured and stored in a memory device of the signal measurement system. In addition to the above waveforms, other display elements such as marker indicators, trigger indicators, etc., are typically displayed.
There are various annotation and documentation requirements that arise during the design, test and evaluation, and other development phases of a circuit or system component, as well as during manufacturing and ongoing support phases. In particular, there is a need for accurate and complete documentation related to signal acquisition and analysis, particularly during product development and manufacturing phases. One such need is to provide the operator with the ability to document test conditions (power usage, load, etc.), observations, suspected causes and proposed solutions to observed behavior of the device under test (DUT). Not only does such information facilitate management of the test and evaluation process, it also facilitates communications with others in the diagnosis of the DUT. There is also a significant need to fully document for subsequent referral all aspects of a test and evaluation procedure, including the resulting test data in addition to the above information. Such documentation may be referred to again until some latter phase of the product development cycle, or even after the product or DUT has gone into its manufacturing phase.
With the advent of increasingly sophisticated signal measurement systems, as well as an increase in the complexity of the devices which are to be tested, such annotation and documentation needs far exceed the capabilities of traditional techniques. One conventional approach has been to provide a simple waveform label containing fixed waveform names. Such labels are typically located in a static region on the left or right side of the waveform display adjacent to the location at which the waveform enters or exits the waveform display region. These labels are often simply channel names or number designations such as, for example, 1, 2, 3 or C1, C2, C3 for waveforms received at channels 1, 2 and 3, respectively. This identification information is useful, particularly in monochrome displays where the use of distinguishing colors or gray scales is limited or non-existent.
However, at most, such conventional techniques provide only a simple indication of which signal waveform is currently displayed. There is no additional information presented and the operator cannot modify or otherwise contribute to the location or content of the displayed label. For example, when multiple waveforms are displayed on a signal measurement system, it is important to provide information beyond channel association such as the location of the circuit (pin 3, IC 5, etc.) associated with the waveform as well as the above information (observations, test conditions, suspected causes of behavioral problems, anticipated solutions to such behaviors, calculations, etc.). The above conventional techniques cannot support such information.
Another common approach is simply to record such information in a laboratory notebook, word processor text file, or the like. It is not uncommon for signals to be measured and the resulting waveforms to be digitally stored and printed. Printed copies of the waveforms, annotated with the above information, are often included in the laboratory notes to supplement the above information. Unfortunately, this approach has also been found to be time consuming and insufficient, particularly with the advent of increasingly sophisticated DUTs and corresponding test procedures.
Subsequent evaluation of the waveforms due to, for example, problems identified during the manufacturing of the DUT, requires a comparison to be made between the current performance of the DUT and the previously-documented characterizations made during product design or component qualification. Unfortunately, the information contained in the above laboratory notes is often incomplete or difficult to correlate with the acquired signals obtained during the current test process. Furthermore, this process is often time consuming or not possible due to the misplacement of the original test results and related information. As a result, additional time must be expended to repeat tests which have been performed previously. Oftentimes, a previous test cannot be repeated due to a change in venders, lack of part inventories, etc. This results in further costs being expended to recharacterize the DUT.
Another conventional approach is implemented in the model 54700 series oscilloscope formally available from Hewlett-Packard Company, Colorado Springs, Colo., USA. To document a measurement in such a conventional signal measurement system, numerous operator actions are typically required to be performed. First, the desired function is selected by pressing a multifunction softkey having a currently assigned function of generating text labels. Typically, the softkey is located near a textual or graphical display at which the key's current function is displayed. With this approach, the current function of the softkey must first be assigned through the activation of a `menu` or `setup` key. The menu/setup key may be a fixed function key located on the front panel, or may itself be a softkey having a currently-assigned function of assigning functions to one or more other softkeys.
The operator must first select each letter or phrase from a list of such letters and phrases to create a desired label. Softkeys or rotational knobs are provided to enable the operator to scroll through a series of optional characters or phrases to arrive at the letter or phrase that the operator desires. To select the letter, the operator depresses an additional softkey indicating acceptance and selection of the highlighted letter or phrase. This process is continually repeated until the operator completes the assembly of the desired text label.
It is also extremely difficult and time-consuming to move the label on the display. First, the operator must select one coordinate, requiring the activation of one or more softkeys. This is followed by the rotation of a knob on the system control panel to move the label along the selected axis. Once the label is in its approximate desired location along the first axis, the operator must then select the orthogonal axis, again through the activation of one or more softkeys. The rotary knob is then rotated to adjust the label along the second axis to the desired position. This sequence of steps is typically repeated until the label is positioned in its desired location.
There are numerous drawbacks to this latter conventional approach. First, it requires numerous key presses and/or knob turns to be implemented in a specified sequence in order to properly generate a label. The series of softkeys and hierarchial layers that the operator must navigate through to generate the labels is difficult to understand and is often difficult to remember, particularly for the novice operator. In addition, considerable time is consumed performing the requisite steps to obtain a desired label. This is particularly problematic when a number of labels are to be generated on different regions of the display. In addition, the time associated with repositioning the labels to their desired locations is extremely time-consuming. Furthermore, the operator is generally not provided with the opportunity to change the appearance of the label, making it difficult to distinguish between multiple labels on a display.
What is needed, therefore, is a simple, intuitive and flexible system and methodology for enabling an operator to clearly annotate and otherwise document test conditions, observations, suspected causes and proposed solutions, to observed DUT behavior, and other desired information related to signal acquisition and analysis. An operator should be able to record such information in a manner that facilitates management of the test and evaluation process including communicating with others in the diagnosis of the DUT. Such information should be easily accessible for later referral as well. The operator should also be able to conveniently adjust the location of the annotation label as well as the appearance of the annotation label on the display.